Mr.Pickle
Smash Lord
Thats probably the most fun follow up I know of after bite. Honestly though, I believe its character dependent to get the guaranteed DACUS, and its probably more optimal to go for an aerial string, with the added possibility of a footstool. Which is something wario mains should explore thoroughly imo.I find that Bite > DACUS works extremely well. if they fail to tech you can get a little charge going on it. At the worst you may get the last hit to make them airborne which is always good for wario.
As far as doubles partners, I find that ganon and charizard have pretty good synergy with him. Though that comes from my personal experience, so I can't speak for everyone.